Rate

> 100

Regularity

Regular

P waves

Inverted, if present

PRI

< 0.12, if P waves are even visible

QRS

0.08-0.12

Rate

Any

Regularity

Regular

P waves

Upright and uniform

PRI

> 0.20

QRS

0.08-0.12

Rate

< 60

Regularity

Regular

P waves

Upright and uniform

PRI

0.12-0.20

QRS

0.08-0.12